如何在回收视图项目中保存按钮状态？

Question

你好，我有一个水平的recyclerview，其中包含一些产品，在加号按钮，我添加产品到购物车，产品添加后的图标变化。我做到了这一点，但我的问题是保存这个按钮的状态，因为当我浏览fragmetsactivities之间，当应用程序启动按钮保持不变。下面是我的情况。

我的适配器里的代码是：

@Override
    public void onBindViewHolder(@NonNull ArtikujtViewHolder holder, int position) {
        final Artikujt mArtikull = artikujt.get(position);

        String mArtikullName = mArtikull.getEmertimet();
        holder.artikullName.setText(mArtikullName);
        String mArtikullCmimi = mArtikull.getCmimi().toString();
        holder.artikullCmimi.setText(mArtikullCmimi+" Leke");

        holder.itemView.setOnClickListener(v -> {
            Intent intent = new Intent(mContext, ProductDetailsActivity.class);
            intent.putExtra("positon", artikujt.get(position));
            intent.putExtra("mArtikullName", mArtikullName);
            intent.putExtra("mArtikullCmimi", mArtikullCmimi);
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            mContext.startActivity(intent);
        });

        SharedPreferences preferences = mContext
                .getSharedPreferences(ITEMS_PREF, MODE_PRIVATE);
        SharedPreferences.Editor mEditor = preferences.edit();

        // using shared preferences to save the state
        if (preferences.contains(ITEMS_PREF)) {
            holder.addItems.setCompoundDrawablesWithIntrinsicBounds(0, 0,
                    R.drawable.ic_check_black, 0);
            holder.addItems.setEnabled(false);
        } else {

        }

        holder.addItems.setOnClickListener(v -> {
            Gson gson = new Gson();
            String json = preferences.getString("artikujtShporta", "");
            ArrayList<Artikujt> artikullObject = gson
                    .fromJson(json, new TypeToken<ArrayList<Artikujt>>(){}.getType());
            if (artikullObject != null) {
                artikullObject.add(mArtikull);
                String jsonString = gson.toJson(artikullObject);
                mEditor.putString("artikujtShporta", jsonString);
                mEditor.apply();
            } else {
                ArrayList<Artikujt> arrayArtikuj = new ArrayList<>();
                arrayArtikuj.add(mArtikull);
                Type listOfTestObject = new TypeToken<ArrayList<Artikujt>>() {}.getType();
                String s = gson.toJson(arrayArtikuj, listOfTestObject);
                mEditor.putString("artikujtShporta", s);
                mEditor.apply();
            }

             holder.addItems.setCompoundDrawablesWithIntrinsicBounds(0, 0,
              R.drawable.ic_check_black, 0);

            //======================================================================================
            // Display a toast message
            final Toast toast = Toast.makeText(mContext, R.string.shtuar_ne_shporte, Toast.LENGTH_SHORT);
            toast.setGravity(Gravity.CENTER_HORIZONTAL, 0, 0);
            toast.show();
            Handler handler = new Handler();
            handler.postDelayed(toast::cancel, 1000);
            //======================================================================================

            assert artikullObject != null;
            count_key = artikullObject.size();

            String cartCount = String.valueOf(count_key);
            Intent my_intent = new Intent("msg");
            my_intent.putExtra("cart_count", cartCount);
            LocalBroadcastManager.getInstance(mContext).sendBroadcast(my_intent);

            v.setEnabled(false);
        });

    }

我找了很多关于这个问题的资料 解决办法可能是用sharedprerences.contains(preferences_id)来保存状态 但是我很困惑. 有没有人有什么建议，我怎么能实现这一点或可能的解决方案.Thanks in advance.

Answer 1

我假设你想保持的是 button 因为它是点击后。

如果这是你的问题，是的，我们将使用。shared prefrences:

@Override
public void onBindViewHolder(@NonNull ArtikujtViewHolder holder, int position) {

//the item
final Artikujt mArtikull = artikujt.get(position);

..........
..........

//read the prefrences
SharedPreferences pref = getSharedPreferences("Button", MODE_PRIVATE);
String state = pref.getString(String.valueOf(position)+"pressed", "no");

if(state.equals("yes")){

//the button must be pressed, make it pressed (check mark icon)

//change the icon
holder.addItems.setCompoundDrawablesWithIntrinsicBounds(0,0,R.drawable.ic_check_black, 0);

holder.addItems.setEnabled(false);

}else{
//the button must not be pressed, make it not pressed (default add icon)

//change the icon
holder.addItems.setCompoundDrawablesWithIntrinsicBounds(0,0,R.drawable.ic_add_icon, 0);

holder.addItems.setEnabled(true);
}


//after clicking the add icon

holder.addItems.setOnClickListener(v -> {

//save to preferences
SharedPreferences.Editor editor = getSharedPreferences("Button", MODE_PRIVATE).edit();
editor.putString(String.valueOf(position)+ "pressed", "yes");
editor.apply();


//change the icon
holder.addItems.setCompoundDrawablesWithIntrinsicBounds(0,0,R.drawable.ic_check_black, 0);
            //======================================================================================
// Display a toast message
final Toast toast = Toast.makeText(mContext, R.string.shtuar_ne_shporte, Toast.LENGTH_SHORT);
toast.setGravity(Gravity.CENTER_HORIZONTAL, 0, 0);
toast.show();
Handler handler = new Handler();
handler.postDelayed(toast::cancel, 1000);
            //======================================================================================

assert artikullObject != null;
count_key = artikullObject.size();

String cartCount = String.valueOf(count_key);
Intent my_intent = new Intent("msg");
my_intent.putExtra("cart_count", cartCount);
LocalBroadcastManager.getInstance(mContext).sendBroadcast(my_intent);

v.setEnabled(false);

});


}

Answer 2

在大多数情况下，保存模型列表中按钮的状态就足够了。但是，当用户改变它的片段或活动时，你的模型列表有可能因为内存的使用而被系统破坏。在这种情况下，你必须选择使用sharedpref，file，db等方式来持久化你的数据，还是将你的数据保存在一个比活动或片段寿命更长的存储中。似乎你分享的页面与你的应用程序的主要功能有关，所以你应该将你的数据保存在一个存储库中，其范围取决于应用程序的范围。我建议你看看mvvm架构和存储库模式。